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This module provides an interface for reading files that use EA IFF 85 chunks.
[1] This format is used in at least the Audio Interchange File Format
(AIFF/AIFF-C) and the Real Media File Format (RMFF). The WAVE audio file format
is closely related and can also be read using this module.

A chunk has the following structure:

Offset

Length

Contents

0

4

Chunk ID

4

4

Size of chunk in big-endian
byte order, not including the
header

8

n

Data bytes, where n is the
size given in the preceding
field

8 + n

0 or 1

Pad byte needed if n is odd
and chunk alignment is used

The ID is a 4-byte string which identifies the type of chunk.

The size field (a 32-bit value, encoded using big-endian byte order) gives the
size of the chunk data, not including the 8-byte header.

Usually an IFF-type file consists of one or more chunks. The proposed usage of
the Chunk class defined here is to instantiate an instance at the start
of each chunk and read from the instance until it reaches the end, after which a
new instance can be instantiated. At the end of the file, creating a new
instance will fail with a EOFError exception.

Class which represents a chunk. The file argument is expected to be a
file-like object. An instance of this class is specifically allowed. The
only method that is needed is read(). If the methods
seek() and tell() are present and don’t
raise an exception, they are also used.
If these methods are present and raise an exception, they are expected to not
have altered the object. If the optional argument align is true, chunks
are assumed to be aligned on 2-byte boundaries. If align is false, no
alignment is assumed. The default value is true. If the optional argument
bigendian is false, the chunk size is assumed to be in little-endian order.
This is needed for WAVE audio files. The default value is true. If the
optional argument inclheader is true, the size given in the chunk header
includes the size of the header. The default value is false.

Set the chunk’s current position. The whence argument is optional and
defaults to 0 (absolute file positioning); other values are 1
(seek relative to the current position) and 2 (seek relative to the
file’s end). There is no return value. If the underlying file does not
allow seek, only forward seeks are allowed.

Read at most size bytes from the chunk (less if the read hits the end of
the chunk before obtaining size bytes). If the size argument is
negative or omitted, read all data until the end of the chunk. An empty
bytes object is returned when the end of the chunk is encountered
immediately.

Skip to the end of the chunk. All further calls to read() for the
chunk will return b''. If you are not interested in the contents of
the chunk, this method should be called so that the file points to the
start of the next chunk.